Julio 2011 - FMVZ-UNAM

Transcription

AÑO 4 *
NUMERO 47 * JULIO 2011
http://www.fmvz.unam.mx/fmvz/departamentos/reproduccion/boletin/actual.html
Julio 2011
1
La PGF2α y el manejo clínico del puerperio
En el ganado lechero las patologías uterinas del puerperio alargan el periodo del parto a la
concepción, disminuyen el porcentaje de concepción al primer servicio, reducen la tasa de vacas
inseminadas, alargan el periodo del parto a la primera ovulación y aumentan el porcentaje de
desecho. La prostaglandina F2α (PGF2α) juega un papel importante en el parto y durante la
involución uterina. En las vacas con puerperio normal la duración de los niveles elevados de PGF2α
está correlacionada negativamente con el tiempo de involución uterina; de esta manera entre más
duren los niveles altos de PGF2α el tiempo de la involución uterina es menor; además, la
administración de PGF2α cada 12 horas del día 3 al 10 posparto acorta el periodo de la involución
uterina. Por el contrario, en las vacas con puerperio anormal se ha observado una correlación
positiva entre las concentraciones de la PGF2α y la involución uterina; de esta manera, las vacas
con retención placentaria o endometritis tienen niveles más altos de PGF2α. Algunas evidencias
involucran a la PGF2α como parte del mecanismo de eliminación de la placenta; así, se ha
observado que las vacas que eliminaron normalmente la placenta tuvieron mayores
concentraciones de PGF2α en los placentomas en comparación con las vacas con retención
placentaria. Se ha propuesto que el fracaso del proceso que conduce a la separación del cotiledón
de la carúncula está asociado con una alteración en el metabolismo de las prostaglandinas que da
como consecuencia una disminución de la PGF2α y un aumento de PGE2. Por otra parte, la
inhibición de la síntesis de PGF2α después del parto mediante la inyección de ácido acetil salicílico
(aspirina) ocasiona retención de la placenta. Estos conocimientos han motivado estudios en los
cuales se ha evaluado el tratamiento con la PGF2α después del parto, para prevenir la retención
placentaria o reducir el tiempo de involución en vacas con retención placentaria o metritis. En
algunos estudios se ha administrado una sola inyección de PGF2α en las primeras horas posparto
con resultados contradictorios. En otros trabajos se ha evaluado la inyección de PGF2α entre los
días 20 a 30 posparto y no se ha observado un efecto favorable en la involución uterina; sin
embargo, la inyección sistemática de PGF2α cada 14 días a partir del día 25 posparto aumenta la
proporción de vacas inseminadas, lo que incrementa la tasa de preñez. La PGF2α provoca
contracciones uterinas y favorece la eliminación de secreciones; sin embargo un efecto favorable de
la PGF2α en la involución uterina sin que haya de por medio un cuerpo lúteo es cuestionable. La
piometra se desarrolla en vacas que ovulan y forman un cuerpo lúteo cuando tienen una infección
uterina. Bajo estas circunstancias la progesterona inhibe al sistema inmunológico, cierra el cérvix,
abate las contracciones uterinas y no ocurre la regresión del cuerpo lúteo; estas vacas muestran un
cuerpo lúteo persistente y responden favorablemente al tratamiento con PGF2α. Alrededor de 30%
de los cuerpos lúteos desarrollados en la primera ovulación posparto tienen una vida media larga
(21 a 50 días), por lo que la inyección de PGF2α cada 14 días acorta el ciclo estral y disminuye el
riego de persistencia de infecciones uterinas. Como se observa la PGF2α tienen un papel muy
importante en el proceso de eliminación de la placenta y en la involución uterina; sin embargo,
todavía no se ha identificado una ventana fisiológica, en la cual su administración favorezca estos
procesos.
Foto de Portada:. Grupo sexualmente activo en un establo lechero del norte de México
Dr. Joel Hernández Cerón
Departamento de Reproducción
Julio 2011
2
Manejo Reproductivo
Journal of Dairy Science Volume 94, Issue 7, Pages 3342-3351, July 2011
Concentration of progesterone during the
development of the ovulatory follicle: I. Ovarian
and embryonic responses
R.L.A. Cerri, R.C. Chebel, F. Rivera, C.D. Narciso, R.A. Oliveira, W.W. Thatcher,
J.E.P. Santos
Objectives were to evaluate the effects of differing
progesterone concentrations during follicle development on
follicular dynamics, fertilization, and embryo quality. Lactating
Holstein cows (n = 154) were assigned randomly to 1 of 2
treatments. Cows underwent a presynchronization of the
estrous cycle composed of an injection of GnRH concurrently
with the placement of a progesterone insert, an injection of
PGF2α and insert removal 7 d later, and a second injection of
GnRH 48 h later (study d −16). All cows were then submitted
to a hormonal protocol identical to the presynchronization
program starting on d 7 of the estrous cycle (study d −9).
Cows enrolled in the high progesterone (HP) treatment
received no further treatment. Cows in the low progesterone
(LP) treatment received additional PGF2α injections on study
d −14, −13.5, and −13 and again on study d −9, −7, −6.5,
and −6. Ovaries were evaluated by ultrasonography, and
blood was sampled for concentrations of progesterone and
estradiol throughout the study. Uteri were flushed 6 d after
artificial insemination (AI) and recovered oocytes-embryos
were evaluated. Concentrations of progesterone were less
for LP cows from study d −7 to −2; concentrations of estradiol
at PGF2α and at the last GnRH of synchronization were
greater for LP than HP. The proportion of cows in estrus at AI
was greater for LP than for HP (38.0 vs. 5.3%). Ovulatory
follicles of LP cows had larger diameters at the injections of
PGF2α (17.2 vs. 14.6 mm) and final GnRH (19.4 vs. 16.9%) of
the synchronization, which resulted in a larger diameter of the
corpus luteum 6 d after AI (24.3 vs. 22.6 mm). Double
ovulation after the last GnRH of the synchronization was
increased in LP (18.6%) compared with HP (4.5%).
Fertilization rate was similar and averaged 82.7%. The
proportion of embryos and oocytes-embryos classified as
grades 1 and 2, proportion of degenerated embryos, and
unfertilized-degenerated oocytes-embryos were not different
between LP and HP. Number of blastomeres did not differ
between LP and HP, but the proportion of live blastomeres
tended to be less for LP than HP (94.2 vs. 98.7%). Reducing
progesterone concentrations during the synchronization
program altered concentrations of estradiol and follicular
dynamics, but resulted in similar fertilization and only minor
changes in embryo quality.
*****
Concentration of progesterone during the
development of the ovulatory follicle: II. Ovarian
and uterine responses
R.L.A. Cerri, R.C. Chebel, F. Rivera, C.D. Narciso, R.A. Oliveira, M. Amstalden,
G.M. Baez-Sandoval, L.J. Oliveira, W.W. Thatcher, J.E.P. Santos
Two experiments evaluated the influence of altering the
concentrations of progesterone during the development of
the ovulatory follicle on the composition of the follicular fluid,
circulating LH and PGF2α metabolite (PGFM), and expression
of endometrial progesterone receptor and estrogen receptorα. In both experiments, the estrous cycles were
presynchronized (GnRH and progesterone insert followed by
insert removal and PGF2α 7 d later, and GnRH after 48 h)
and cows were then enrolled in 1 of 2 treatments 7 d later
(study d −16): high progesterone (HP) or low progesterone
(LP). In experiment 1 (n = 19), cows had their estrous cycle
synchronized starting on study d −9 (GnRH and
progesterone insert on d −9, and insert removal and PGF2α
on d −2). In experiment 2 (n = 25), cows were submitted to
the same synchronization protocol as in experiment 1, but
had ovulation induced with GnRH on study d 0. In experiment
1, plasma was sampled on d −4 and analyzed for
concentrations of LH; the dominant follicle was aspirated on d
0 and the fluid analyzed for concentrations of progesterone,
estradiol, and free and total IGF-1. In experiment 2, follicular
development and concentrations of progesterone and
estradiol in plasma were evaluated until study d 16. Uterine
biopsies were collected on d 12 and 16 for progesterone
receptor and estrogen receptor-α protein abundance. An
estradiol/oxytocin challenge for PGFM measurements in
plasma was performed on d 16. In experiments 1 and 2, LP
cows had lower plasma concentrations of progesterone and
greater concentrations of estradiol, and had larger ovulatory
follicle diameter (20.4 vs. 17.2 mm) at the end of the
synchronization protocol than HP cows. Concentration of LH
tended to be greater for LP than HP cows (0.98 vs. 0.84
ng/mL). The dominant follicle of LP cows had greater
concentration of estradiol (387.5 vs. 330.9 ng/mL) and a
Julio 2011
3
lower concentration of total IGF-1 (40.9 vs. 51.7 ng/mL) than
that of HP cows. In experiment 2, estradiol and progesterone
concentrations did not differ between treatments from d 0 to
16; however, the proportion of cows with a short luteal phase
tended to increase in LP than HP (25 vs. 0%).
Concentrations of PGFM were greater for LP than HP.
Uterine biopsies had a greater abundance of progesterone
receptor, and tended to have less estrogen receptor-α
abundance on d 12 compared with d 16. An interaction
between treatment and day of collection was detected for
estrogen receptor-α because of an earlier increase in protein
abundance on d 12. Reduced concentrations of progesterone
during the development of the ovulatory follicle altered
follicular dynamics and follicular fluid composition, increased
basal LH concentrations, and prematurely increased
estrogen receptor-α abundance and exacerbated PGF2α
release in the subsequent estrous cycle.
*****
Animal Reproduction Science 126 (2011) 23–31
Cryopreservation of bull semen shipped
overnight and its effect on post-thaw sperm
motility, plasma membrane integrity,
mitochondrial membrane potential and normal
acrosomes
M. Anzara,*, T. Kroetschb, L. Boswalla
a Canadian Animal Genetic Resource Program, Agriculture and Agri-Food Canada,
Saskatoon, Saskatchewan, Canada
b Semex-Alliance, Guelph, Ontario, Canada
In the Canadian Animal Genetic Resource Program, bull
semen is donated in frozen or fresh (diluted) states. This
study was designed to assess the cryopreservation of diluted
bull semen shipped at 4 C overnight, and to determine the
post-thaw quality of shipped semen using different straw
volumes and freezing rates. Semen was collected from four
breeding bulls (three ejaculates per bull). Semen was diluted
in Tris-citric acid-egg yolk-glycerol (TEYG) extender, cooled
to 4°C and frozen as per routine (control semen). After
cooling to 4°C, a part of semen was removed and shipped
overnight to the research laboratory via express courier
(shipped semen). Semen was packaged in 0.25 or 0.5ml
straws and frozen in a programmable freezer using three
freezing rates, i.e., -10, -25 or -40°C/min. Control semen was
also shipped to the research laboratory. Post-thaw sperm
motility characteristics were assessed using CASA, and postthaw sperm plasma membrane, mitochondrial membrane
potential and normal acrosomes were assessed using flow
cytometry. Post-thaw sperm quality was greater in shipped
semen as compared to control (P<0.001). The shipped
semen packaged in 0.25ml straws had better post-thaw
sperm quality than in 0.5ml straws (P<0.001). Freezing rate
had no effect on post-thaw sperm quality. In conclusion, bull
semen can be shipped overnight for subsequent
cryopreservation and gene banking. Overnight shipping of
semen was found advantageous for bull semen
cryopreservation. Semen packaging in 0.25ml straws yielded
better post-thaw quality than 0.5ml straws.
* Corresponding author at: E-mail addresses: [email protected],
[email protected] (M. Anzar).
*****
Efficacy of embryo transfer in lactating dairy
cows during summer using fresh or vitrified
embryos produced in vitro with sex-sorted
semen
B.M. Stewart, J. Block, P. Morelli, A.E. Navarette, M. Amstalden, L. Bonilla, P.J.
Hansen, T.R. Bilby
The objective was to determine whether transfer of fresh or
vitrified embryos produced in vitro with sex-sorted semen
improves pregnancy and calving rates during summer in
lactating dairy cows compared with artificial insemination (AI).
Lactating dairy cows (n = 722) were enrolled during summer
months at 2 commercial dairies in Central Texas and
randomly assigned to 1 of 3 treatments: AI with conventional
semen (n = 227), embryo transfer-vitrified (ET-V; n = 279) or
embryo transfer-fresh (ET-F; n = 216). Embryos were
produced in vitro using sex-sorted semen and with BlockBonilla-Hansen-7 culture medium. For vitrification, grade 1
expanded blastocysts were harvested on d 7 after fertilization
and vitrified using the open-pulled straw method. Fresh
embryos were grade 1 blastocysts and expanded blastocysts
harvested on d 7 after fertilization. Cows were submitted to
the Ovsynch56 protocol: d −10 GnRH, d −3 PGF2α, d −1
GnRH and d 0 timed AI; or Select Synch protocol: d −9
GnRH, d −2 PGF2α, and AI following detected estrus (day of
AI = d 0). On d 7, all cows were examined for presence of a
corpus luteum (CL). A vitrified or fresh embryo was
transferred to cows with CL in ET-V and ET-F groups. Cows
were considered synchronized if progesterone was <1 ng/mL
on d 0 and a CL was present on d 7. At d 40 ± 7 of gestation,
the percentage of cows pregnant was greater for the ET-F
compared with the ET-V and AI groups among all cows (42.1
Julio 2011
4
vs. 29.3 and 18.3%, respectively) and synchronized cows
(45.5 vs. 31.6 and 24.8%, respectively). Also, the percentage
of cows pregnant was greater for the ET-V than the AI group
among all cows and tended to be greater among
synchronized cows. At d 97 ± 7 of gestation, the percentage
of cows pregnant among all cows was greater for ET-F and
ET-V groups than for the AI group (36.4 and 25.7 vs. 17.0%,
respectively) and the percentage for the ET-F group was
greater than for the ET-V group. Among synchronized cows,
the percentage of cows pregnant was significantly increased
for the ET-F group than for ET-V and AI groups (39.4 vs. 27.8
and 23.1%, respectively) and no difference was found
between ET-V and AI groups. No effect of treatment on
embryo loss was observed. The percentage of cows with live
births was significantly increased for the ET-F than for ET-V
and AI groups among all cows (27.5 vs. 17.1 and 14.6%,
respectively) and synchronized cows (29.9 vs. 18.5 and
20.0%, respectively). The percentage of cows giving birth to
a live heifer was significantly increased for the ET-F and ETV groups compared with the AI group among all cows (79.1
and 72.5 vs. 50.0%, respectively) and synchronized cows
(79.1 and 72.5 vs. 50.0%, respectively). No difference existed
between ET-F and ET-V groups for percent live heifer births
but both were greater than for the AI group. The transfer of
fresh embryos produced in vitro using sex-sorted semen to
lactating dairy cows during summer can effectively increase
the percentage of cows that establish pregnancy and also the
percentage of cows that give birth to a live heifer compared
with percentages from AI with conventional semen.
*****
Epidural vs intramuscular administration of
lecirelin, a GnRH analogue, for the resolution of
follicular cysts in dairy cows
Rizzo Annalisa, Campanile Debora, Mutinati Maddalena, Minoia Giuseppe,
Spedicato Massimo, Sciorsci Raffaele Luigi *
Department of Animal Production, Faculty of Veterinary Medicine, University of Bari
Aldo Moro, Strada Prov. le per Casamassima, Km 3, 70010 – Valenzano (Bari), Italy
Bovine follicular cysts are an ovarian disorder of dairy cows
associated with abnormal estrous behaviour and infertility.
The treatment of choice is intramuscular administration of a
GnRH analogue, which acts by triggering pituitary release of
LH. However, the presence of GnRH and GnRH receptors on
spinal cord and ovary in some species, and the kind of
innervation of the ovary, let us hypothesize that GnRH and its
analogues may also act when administered by epidural route,
as happens for other drugs. Therefore the aim of this study
was to compare the effects of epidural vs intramuscular
administration of lecirelin (a GnRH analogue) on FC
regression, estrus detection and pregnancy outcomes.
The study was conducted on 220 Friesian cows affected by
follicular cysts, divided among 4 groups: Group Lepid and
Group Lim received, respectively 50µg of lecirelin in the
epidural space and intramuscular; Group Cepid and Group
Cim were used as control groups. In Group Lepid, estrus
induction and pregnancy rates were significantly higher than
in Group Lim.
The results of this study show that the epidural administration
of lecirelin promoted the remission of follicular cysts and an
improvement of reproductive parameters compared to
intramuscular administration.
Thus, an alternative therapeutical approach is available for
FC treatment, in order to obtain an easier restoration of the
ovarian activity, especially in those cases refractory to
classical therapeutic approaches.
∗ Corresponding author. E-mail address: [email protected] (S.R. Luigi).
*****
Theriogenology 76 (2011) 320–327
Exogenous progesterone enhances ova and
embryo quality following superstimulation of the
first follicular wave in Nelore (Bos indicus)
donors
L.F. Nassera,b,*, M.F. Sá Filhob, E.L. Reisb, C.R. Rezendec, R.J. Mapletoftd, G.A.
Bóe, P.S. Barusellib,*
a Born Animal Biotechnology – Panama Corp., Panamá City, Panamá
b Department of Animal Reproduction, São Paulo, SP, Brazil
c Firmasa Tecnologia para pecuária, LTDA., Campo Grande, MS, Brazil
d University of Saskatchewan, Saskatoon, SK, Canada
e Instituto de Reproducción Animal Córdoba, Córdoba, Argentina
Three experiments were conducted to evaluate the effects of
exogenous progesterone on superovulatory response and
ova/embryo quality in Bosindicus donors superstimulated
during the first follicular wave (FFW). We hypothesized that
exogenous progesterone during gonadotropin treatments
would improve ova and embryo quality. In Experiment 1, 18
Nelore cows were randomly allocated to three groups: (1)
FFW; (2) FFW plus a progesterone-releasing device
(FFW+P4); and (3) control (E2+P4). Cows in the FFW groups
were superstimulated beginning at synchronized ovulation,
Julio 2011
5
whereas cows in the control group were superstimulated after
synchronization of follicular wave emergence with estradiol
plus progesterone (E2+P4). There were no differences in
mean (± SD) numbers of transferable embryos between
FFW+P4 (8.0 ± 4.5) and control (6.7 ± 4.8) groups, but both
were higher (P = 0.006) than the FFW group (0.2 ± 0.4). In
Experiment 2, FFW and FFW+P4 were compared in 20
Nelore donors; exogenous progesterone increased the
number of transferable embryos (3.9 ± 3.4 vs. 1.3 ± 4.1, P =
0.003). In Experiment 3, FFW and FFW+P4 were compared
in 10 Nelore donors except that cows were slaughtered 12 h
after pLH (Lutropin-V(®), Bioniche Animal Health, Belleville,
ON, Canada) treatment. More mature cumulus oocyte
complex (COC) (expanded cumulus cell layers) were
collected in the FFW+P4 group than in the FFW group (21.8
± 13.1 vs. 10.8±14.7; P = 0.003). In summary,
superovulatory response was satisfactory when FSH
(Folltropin-V(®), Bioniche Animal Health) treatment was
initiated at emergence of the first follicular wave in Nelore
(Bos indicus) donors, and the hypothesis that administration
of exogenous progesterone during the treatment will improve
oocyte and embryo quality was supported.
* Corresponding author: E-mail address: [email protected] (L.F. Nasser)
and barusell@ usp.br (P.S. Baruselli).
*****
Incidence of metabolic disorders and
reproductive performance following a short (35d) or conventional (60-d) dry period
management in commercial Holstein herds
D.E. Santschi, D.M. Lefebvre, R.I. Cue, C.L. Girard, D. Pellerin
A total of 850 Holstein cows from 13 commercial dairy herds
were involved in the present study to compare the effects of 2
different dry period (DP) management strategies on health
and reproductive parameters. Cows were assigned to either
a short (SDP; 35-d) or a conventional (CDP; 60-d) DP
management within each herd, based on previous 305-d milk
yield, parity (414 primiparous and 436 multiparous), and
estimated calving interval. Cows assigned to CDP were fed a
dry cow ration from dry-off until 21 d prepartum, and were
then switched to a precalving ration. Cows assigned to SDP
were fed the precalving ration throughout their DP. Rations
were specific to each herd. A significant treatment × parity
interaction was found for culling rate. Dry period
management did not affect culling rate for second-lactation
cows but a significantly higher culling rate occurred in
multiparous CDP cows compared with SDP (42.6 vs. 31.6%
± 3.7 for CDP and SDP, respectively). Management used in
the DP did not affect incidence of severe ketosis, displaced
abomasum, milk fever, and mastitis, although incidence of
these metabolic disorders were lower in second-lactation
than third- or greater-lactation cows. The incidence of mild
ketosis (evaluated by milk ketone concentration) was lower
following SDP, probably as a result of better energy balance.
On the other hand, the incidence of retained placenta was
higher in multiparous cows assigned to SDP, but the reason
for this increase remains unclear. Nevertheless, this did not
lead to increased incidence of metritis. Moreover, DP
management did not influence reproductive measures,
including days in milk at first breeding, number of breedings
per conception, as well as conception rates at first and
second services. Regarding days open, overall, all 13 herds
were not significantly affected by treatment, but 1 herd clearly
showed opposite results to the 12 others. Our results indicate
that a short DP management strategy could facilitate
transition from one lactation to the next by decreasing the
incidence of mild ketosis, with no major negative effects on
other health parameters and reproduction. The variation in
results observed among herds suggests that other
management practices influence the response observed
following a short or conventional DP, emphasizing the need
for other field studies.
*****
Relationships between cytology, bacteriology
and vaginal discharge scores and reproductive
performance in dairy cattle
Scott McDougalla,*, Hassan Husseina, Danielle Aberdeinb, Kelly Buckleb, John
Rochec, Chris Burkec, Murray Mitchelld, Susanne Meierc
a Animal Health Centre, PO Box 21, Morrinsville, New Zealand
b Institute of Veterinary, Animal and Biomedical Sciences, Massey University,
Palmerston North, New Zealand
c DairyNZ, Private Bag 3221, Hamilton, New Zealand
d University of Queensland Centre for Clinical Research, Brisbane, Australia, and
Liggins Institute, University of Auckland, Private bag 92019, Auckland, New Zealand
The objective was to compare three diagnostic approaches
for intrauterine infection and inflammation: scoring of vaginal
contents; quantification of percentage of nucleated cells that
were polymorphonuclear leukocytes (PMN) following
endometrial cytology; and intra-uterine bacteriology. Dairy
cows (n = 303) were examined twice, Days 28 (D28) and 42
(D42), where Day 0 = day of calving. Associations between
Julio 2011
6
gross vaginal inflammation scores, uterine cytology, and
bacteriology, and subsequent reproductive performance were
examined using multivariable models. There was fair
agreement at D28 (Kappa = 0.29), but only slight agreement
at D42 (Kappa < 0.15), between PMN% and gross vaginal
inflammation score. Cows were categorized as having
PMN% in the highest quartile (H), or not (L), at both D28 and
D42; therefore, cows were categorized as PMNLL, PMNLH,
PMNHL, or PMNHH. Cows in the highest PMN% quartile at
both time periods were slower to conceive (P < 0.001) than
those in all other quartiles (mean ± SEM 32.2 ± 2.3, 37.0 ±
5.3, 40.8 ± 4.1, and 55.3 ± 7.3 d from start of breeding to
conception for PMNLL, PMNLH, PMNHL, and PMNHH
PMN% cows, respectively). Milk yield was greater (P =
0.001) in cows in the lower quartiles for PMN% at D28 and
D42 (i.e., PMNLL) than those in the PMNHH and PMNHL
categories, with PMNLH intermediate (P = 0.001). We
concluded that PMN% was a better predictor of reproductive
performance than either intra-uterine bacteriology or
gross vaginal inflammation score. Cows in the highest
quartile for PMN% at both D28 and D42 had lower pregnancy
rates, took longer to conceive, and had a lower milk yield
than those in the lower PMN% categories.
supplemented with 75 g of urea/day), following a cross-over
design. Heifers received their respective diets for 6 d (without
adaptation). On the sixth day, blood samples were harvested
both before and 3 h after feeding, and cumulus oocyte
complexes (COCs) were collected by ovum pick-up. Although
PUN concentrations were higher in UREA than CONTROL
heifers (31.31 mg/dL ± 1.13 vs 22.12 mg/dL ± 0.86; mean ±
SEM), neither the number of COCs recovered (8.8 ± 1.0 vs
9.2 ± 0.8, UREA vs CONTROL, respectively) nor their quality
(based on morphology) differed significantly between groups.
Next, oocytes were fertilized and cultured in vitro to assess
developmental rates. There was an absence of significant
differences between groups for rates of cleavage (Day 3) or
blastocyst formation (Days 6, 7 and 9), but the hatched
blastocyst rate on Day 11 after fertilization was lower (P <
0.05) in the UREA than the CONTROL groups (64.3 vs
83.5%). Therefore, we inferred that the effects of urea were
only manifest later in development. In conclusion, high PUN
concentrations decreased oocyte competence in heifers,
reinforcing the hypothesis that poor reproductive
performance in cows with high PUN was due, at least in part,
to a deleterious effect on oocytes.
* Corresponding author. E-mail address: [email protected] (M. Binelli).
* Corresponding author. E-mail address: [email protected] (S. McDougall).
*****
*****
Short-term urea feeding decreases in vitro
hatching of bovine blastocysts
F.A. Ferreiraa, R.G.G. Gomezb, D.C. Joaquimb, Y.F. Watanabeb, L.A. de Castro e
Paulac, M. Binellia,*, P.H.M. Rodriguesa
a Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo
(USP), Avenida Duque de Caxias Norte, 225, Pirassununga, São Paulo, Brazil
b Vitrogen Pesquisa e Desenvolvimento em Biotecnologia de Reprodução, Avenida
Coronel José Nogueira Terra, 203, Cravinhos, São Paulo, Brazil
c Independent Veterinarian, Rua Alves Guimarães, 408/52, São Paulo, SP, Brazil
Cows fed high-protein diets may have impaired reproductive
performance. Although the pathogenesis has not been
completely elucidated, it appears that not only the uterus, but
also the follicle and oocyte, are affected by excessive plasma
urea nitrogen (PUN) concentrations. Thus, the objective was
to determine the effects of short-term urea feeding on the
competence of bovine oocytes. Forty crossbred heifers (Bos
indicus vs Bos taurus) were allocated to two groups, namely
CONTROL (maintenance diet) and UREA (maintenance diet
Julio 2011
7
Artículos de Revisión
Reproduction (2011) 141 715–724
A balancing act: mechanisms by which the fetus
avoids rejection by the maternal immune system
J C Warning, S A McCracken and J M Morris1
Department of Perinatal Research, Kolling Institute of Medical Research, University
of Sydney at Royal North Shore Hospital, Sydney, New South Wales 2065, Australia
and 1Department of Obstetrics and Gynaecology, Northern Clinical School,
University of Sydney, Sydney, New South Wales 2065, Australia
Successful pregnancy requires strict temporal regulation of
maternal immune function to accommodate the growing
fetus. Early implantation is facilitated by inflammatory
processes that ensure adequate vascular remodeling and
placental invasion. To prevent rejection of the fetus, this
inflammation must be curtailed; reproductive immunologists
are discovering that this process is orchestrated by the fetal
unit and, in particular, the extravillous trophoblast. Soluble
and particulate factors produced by the trophoblast regulate
maternal immune cells within the decidua, as well as in the
periphery. The aim of this review is to discuss the action of
recently discovered immunomodulatory factors and
mechanisms, and the potential effects of dysregulation of
such mechanisms on the maternal immune response that
may result in pregnancy loss or preeclampsia.
Correspondence should be addressed to J M Morris; Email:
[email protected]
*****
The role of nutritional supplementation on the
outcome of superovulation in cattle
M.A. Velazquez *
Escuela Superior de Ciencias Agropecuarias, Universidad Autónoma de Campeche,
Calle 53 s/n, C.P. 24350, Escárcega, Campeche, México
Since the 1990s nutritional supplements including protein,
fatty acids, vitamins, and minerals have been used to try and
improve the superovulatory response of embryo donors in
cattle. However, the accumulated information indicates that
nutritional supplementation with protein, fatty acids, or
minerals does not increase the number of viable embryos
from superovulated cattle. Most of the evidence has shown
that vitamin supplementation may increase the mean
production of transferable embryos, but only in cows, as a
detrimental effect on embryo viability has been reported in
young heifers. Nevertheless, vitamin supplementation seems
to be effective only when compared with control cows
displaying a poor mean embryo production (i.e. less than four
viable embryos), questioning the economical significance of
such approach. Detrimental effects on embryo development
have been reported in superovulated cattle supplemented
with protein or fatty acids as well. New approaches to
investigate the role of nutritional supplementation on
superovulatory outcome in cattle are suggested in the
present review. Overall, the available evidence indicates that
nutritional supplementation strategies tested are not an
effective approach to enhance the superovulatory outcome of
well-fed cattle donors.
*. E-mail address: lestaurus [email protected]
*****
Reprod Dom Anim 46, 534–553 (2011)
Male Reproductive Traits and Their Relationship
to Reproductive Traits in Their Female Progeny:
A Systematic Review
BM Burns1, C Gazzola2, RG Holroyd2, J Crisp3 and MR McGowan3
University of Queensland, Centre for Animal Science, Queensland Alliance for
Agriculture and Food Innovation, Rockhampton, Qld, Australia; 2Department of
Employment, Economic Development and Innovation, Rockhampton, Qld, Australia;
3The University of Queensland, School of Veterinary Science, Gatton, Qld, Australia
1The
The overall objective of one of the major research programs
in the Co-operative Research Centre (CRC) for Beef Genetic
Technologies is to 'Improvefemale reproductive performance'
in tropical, northern Australian beef cattle herds. To address
this overall objective, a quantitative genetics project focused
on investigation of male reproductive traits was designed and
linked to three female reproduction-focussed projects, (i)
discovery of genes associated with post-partum reconception and age at puberty; (ii) expression of genes
associated with post-partum re-conception; and (iii) early
predictors of lifetime female reproductive performance.
During the initial planning of this male reproductive traits
project, the CRC Scientific ReviewCommittee recommended
that the research team investigate and evaluate potentially
new, early-life (i.e able to be measured before 2 years of
age) predictors of both male and female reproductive
performance. To address this recommendation, the following
was carried out: (i) criteria for selection of traditional and
candidate traits were established; (ii) methodology for
tabulation of potential traits/phenotypes that define male
Julio 2011
8
andfemale reproductive function was developed; and (iii) a
systematic scientific review of early-life predictors of male
and female fertility was prepared. This review concluded that
although factors that might be useful in predicting male
reproductive performance have been studied for many years,
there was relatively little useful information available to meet
the objectives of this review. It was also concluded that the
direction of future research should be guided not only by
previous research which was scarce, but also by speculative
hypotheses arising from an understanding of the
physiological, endocrinological and genetic processes active
in reproduction. A small number of new traits were
recommended in addition to traditional sperm morphology,
sexual behaviour, anatomical structure and growth traits.
Potential additional traits include measurement of
gonadotrophin-releasing hormone-stimulated luteinizing
hormone (GnRH-stimulated LH); inhibin; several seminal
plasma proteins (osteopontin, spermadhesin and seminal
plasma proteins BSP30 and phospholipase A(2) could be
used in an index); 11β-hydroxysteriod dehydrogenase; and
leptin. In addition, the potential also exists to screen animals
for a number of genetic markers associated with age of
puberty, follicular recruitment and ovulation rate and genes
associated with bovine seminal plasma protein and
testosterone production. Insulin-like growth factor-1 (IGF-1)
measurements are included because of their association with
growth parameters, and an additional analysis demonstrated
associations with maleand female reproductive traits. Some
of these factors have been previously evaluated in small
numbers of animals of various species under intensive
management conditions. Therefore, there is a need to
evaluate these factors in much larger numbers of beef cattle
grazing semi-extensive tropical production systems in
northern Australia to determine their value in improving beef
cattle enterprise profitability through improved herd fertility.
Author’s address: BM Burns. E-mail: brian.burns@deedi. qld.gov.au or
[email protected]
*****
Julio 2011
9
Fisiología Reproductiva
Association between endometritis and
endometrial cytokine expression in postpartum
Holstein cows
K.N. Galvãoa,b, N.R. Santosa, J.S. Galvãoa, R.O. Gilberta,*
a Department of Clinical Sciences, Cornell University, Ithaca, New York, USA
b Present address: Department of Large Animal Clinical Sciences, College of
Veterinary Medicine, University of Florida, Gainesville,
Florida, USA
The endometrium regulates the inflammatory response after
infection by production and release of cytokines and
chemokines. The objective was to compare gene expression
of important pro-inflammatory (TNFα, IL-1β, IL-6) and antiinflammatory (IL-10) cytokines, and the main neutrophil
chemokine (IL-8), from calving to Week 7 after calving, in
cows that developed endometritis and healthy control cows.
Uterine biopsies were obtained at calving and at Weeks 1, 3,
5 and 7. Endometritis was evaluated at Week 5 by uterine
lavage and cytology; cows with ≥ 10% neutrophils were
considered to have endometritis. Real-time RT-PCR
threshold values (Ct) were used to calculate the fold
difference in gene expression, using the 2(-ddCt) method,
normalized to GAPDH and calibrated to the average dCt for
all cows at calving. Serum IL-8 concentrations were
measured with ELISA. The analysis included 28 cows (11
had endometritis) for the PCR data and 44 cows (20 had
endometritis) for ELISA. Expression of the TNFα gene in
uterine tissue was decreased in cows with endometritis
compared to control cows at calving (P = 0.09) and at Week
1 (P = 0.05). Iterleukin-1β gene expression tended to be
decreased (P = 0.08) in cows with endometritis compared to
control cows at Week 1, but tended to be increased (P ≤
0.10) at Weeks 5 and 7. Cows with endometritis had
increased (P < 0.05) IL-6 gene expression at calving and at
Week 7 compared to controlcows. Interleukin-8 gene
expression was increased (P = 0.03) in endometritic cows
compared to control cows at Week 7. Uterine disease was
not significantly associated with IL-10 gene expression. A
lower local level of expression of pro-inflammatory cytokines
in the endometrium soon after calving might impair activation
of inflammation and clearance of bacteria, and lead to
development of endometritis.
Biology of Reproduction 85, 144–156 (2011)
Conceptus-Induced Changes in the Endometrial
Transcriptome: How Soon Does the Cow Know
She Is Pregnant?1
N. Forde,2,3 F. Carter,3 T.E. Spencer,5 F.W. Bazer,5 O. Sandra,6 N. MansouriAttia,3 L.A. Okumu,3 P.A. McGettigan,3 J.P. Mehta,3 R. McBride,4 P. O’Gaora,4
J.F. Roche,3 and P. Lonergan3,4
School of Agriculture, Food Science and Veterinary Medicine,3 Conway Institute,4
University College Dublin, Belfield, Dublin, Ireland
Center for Animal Biotechnology and Genomics,5 Department of Animal Science,
Texas A&M University, College Station, Texas
Institut National de la Recherche Agronomique,6 Unité Mixte de Recherche 1198
Biologie du Développement et Reproduction, Jouy en Josas, France
This study sought to determine the earliest response of the
bovine uterine endometrium to the presence of the conceptus
at key developmental stages of early pregnancy. There were
no detectable differences in gene expression in endometria
from pregnant and cyclic heifers on Days 5, 7, and 13
postestrus, but the expression of 764 genes was altered due
to the presence of the conceptus at maternal recognition of
pregnancy (Day 16). Of these 514 genes, MX2, BST2,
RSAD2, ISG15, OAS1, USP18, IFI44, ISG20, SAMD9,
EIF4E, and IFIT2 increased to the greatest extent in pregnant
endometria (>8-fold log2 fold change increase). The
expression of OXTR, Bt.643 (unofficial symbol), and
KCNMA1 was reduced the most, but short-term treatment
with recombinant ovine interferon tau (IFNT) in vitro or in vivo
did not alter their expression. In vivo intrauterine infusion of
IFNT induced the expression of EIF4E, IFIT2, IFI44, ISG20,
MX2, RSAD2, SAMD9, and USP18. These results revealed
for the first time that changes that occur in the endometrial
transcriptome are independent of the presence of a
conceptus until pregnancy recognition. The differentially
expressed genes (including MX2, BST2, RSAD2, ISG15,
OAS1, USP18, IFI44, ISG20, SAMD, and EIF4E) are a
consequence of IFNT production by the conceptus. The
identified genes represent known and novel early markers of
conceptus development and/or return to cyclicity and may be
useful to identify the earliest stage at which the endometrial
response to the conceptus is detectable.
2Correspondence:
e-mail: [email protected]
*****
* Corresponding author: E-mail address: [email protected] (R.O. Gilbert).
*****
Julio 2011
10
J Anim Sci.2011 Jul;89(7):2086-95.
Effects of immunization against luteinizing
hormone-releasing hormone and treatment with
trenbolone acetate on reproductive function of
beef bulls and steers
Geary TW, Wells KJ, Deavila DM, Deavila J, Conforti VA, McLean DJ, Roberts
AJ, Waterman RW, Reeves JJ.
USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT
59301.
The objectives of this study were 1) to evaluate the ability of
trenbolone acetate (TBA) administered in tandem with LHRH
immunization to suppress reproductive function in bulls and
2) to examine the effects of LHRH and androgen (TBA)
signaling on pituitary gland function. Forty-four Angus ×
Hereford crossbred calves (BW = 225 ± 2 kg; age = 187 ± 6
d) received castration, LHRH immunization, or TBA
administration in a 2 × 2 × 2 factorial design. Treatment
groups receiving LHRH immunization contained 6 animals,
whereas other treatment groups contained 5 animals.
Animals immunized against LHRH received a primary
injection and 2 booster injections of ovalbumin-LHRH-7
fusion protein on d 0, 42, and 196, respectively. Animals
treated with TBA were implanted on d 224. Serum LHRH
antibodies increased (P < 0.05) after each booster for
immunized animals, but were negligible in nonimmunized
animals throughout the experiment. Serum testosterone
concentration (P < 0.001) and scrotal circumference (P <
0.05) were depressed in LHRH-immunized bulls compared
with nonimmunized bulls by d 84 and 168 of the experiment,
respectively. Treatment with TBA tended (P = 0.08) to
decrease
serum
testosterone
concentrations
of
nonimmunized bulls. Weights of testes at slaughter were
decreased (P < 0.001) for LHRH-immunized (232 ± 41 g)
compared with nonimmunized (752 ± 45 g) bulls, but did not
differ (P= 0.80) between TBA-implanted (500 ± 49 g) and
nonimplanted bulls (484 ± 36 g). Both LHRH immunization
and castration decreased pituitary gland stores of LH and
FSH (P < 0. 001). There was no effect (P > 0.10) of TBA on
pituitary gland FSH content and only a tendency (P = 0.09) to
increase pituitary gland LH content. Immunization against
LHRH decreased expression of LH β-subunit and common αsubunit genes (P < 0.001). Castration increased expression
of LH β-subunit and common α-subunit genes (P = 0.02).
Treatment with TBA further suppressed (P = 0.04) α-subunit
mRNA expression in LHRH-immunized steers. In summary,
LHRH immunization decreased synthesis and storage of LH
and decreased storage, but not synthesis of FSH in bulls.
The increased synthesis of LH and FSH in nonimmunized,
but not LHRH-immunized steers suggests that castration
removes the negative feedback on gonadotropin synthesis
but that LHRH is still needed for release of these hormones.
Androgen replacement with TBA did not restore the negative
feedback control of gonadotropin synthesis.
*****
Production and health assessment of secondgeneration cloned Holstein cows derived by
somatic cell nuclear transfer
H. Wanga,b,1, J.X. Zhangc,d,1, M.B. Zhaoc, X.L. Zhangc, Q.Y. Suna,2, D.Y. Chena,*,2
a State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese
Academy of Sciences, Beijing 100080, China
b The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School,
Norfolk, VA 23507, USA
c Beijing Gloriousland Agricultural Co., Ltd., Beijing 100039, China
d College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner
Mongolia 010018, China
In this study we evaluated cloning efficiency of secondgeneration (G2) cloned Holstein cows derived from ear
fibroblasts of a first-generation (G1) cloned cow, and
assessed their health status in terms of physical, growth and
reproductive parameters. Compared with G1 cloning, G2
cloning showed a slight decrease on blastocyst rate of
reconstructed embryos (30.2±5.8% vs. 28.5±7.2%, p>0.05),
while the quality of its blastocysts reduced significantly
(Grade 1 and Grade 2, 21.1±4.1% vs. 17.1±5.7%, p<0.05).
After embryo transfer (ET), both pregnancy rate to term and
calving rate of G2 cloning were approximately half of G1
cloning (5.8% vs. 10.7%; 3.9% vs. 8.6%, p>0.05). Six G2
cloned cows were delivered, and three of them survived. G2
cloned calves displayed symptoms of being overweight at
birth and tachycardia in the first week after birth. During the
first 12 months, the growth of G2 cloned calves was similar to
control calves derived from artificial insemination (AI).
Furthermore, the interindividual variation of growth within the
G2 clonal family was smaller except at birth and at two
months of age. Interestingly, although G2 cloned cows
reached puberty 45 days later in comparison with control
cows derived from AI, they were all pregnant by AI, and gave
birth to healthy calves. This suggests that their reproductive
performance was not affected by late puberty. In summary,
our results showed that although cloning efficiency of G2 was
lower than that of G1, the surviving G2 clones appeared
physically healthy and were fertile.
* Corresponding author. E-mail addresses: [email protected], [email protected]
(D.Y. Chen).
*****
Julio 2011
11
Reproduction (2011) 141 779–787
Evaluation of bovine zona pellucida
characteristics in polarized light as a prognostic
marker for embryonic developmental potential
M Koester, A Mohammadi-Sangcheshmeh1, M Montag, F Rings1, T
Schimming2, D Tesfaye1, K Schellander1 and M Hoelker1
Department of Gynecological Endocrinology and Reproductive Medicine, University
of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany, 1Animal Breeding and
Husbandry Group, Institute of Animal Science, University of Bonn, Endenicher Allee
15, 53115 Bonn, Germany and 2Octax Microscience GmbH, Dr-Pauling-Strasse 9,
84079 Bruckberg, Germany
It has previously been demonstrated that zona pellucida
imaging of human oocytes using polarized light microscopy is
a clinically applicable method for the noninvasive assessment
of oocyte quality. This study was designed to investigate
whether zona pellucida characteristics of bovine oocytes and
zygotes in polarized light may similarly serve as a useful
marker for developmental competence in bovine reproductive
biotechnologies. Zona birefringence intensity parameters of
2862 oocytes/zygotes were objectively evaluated with an
automatic analysis system and correlated with oocyte/zygote
quality. In detail, immature oocytes of good quality assessed
with brilliant cresyl blue staining showed significantly lower
zona birefringence than poor-quality counterparts (P<0.001).
After in vitro maturation and classification according to
maturational status, the birefringence intensity parameters
were significantly different in those oocytes that reached
metaphase II compared with arrested stages (P<0.001).
Following either parthenogenetic activation or IVF with
subsequent in vitro culture in a well-of-the-well system until
day 9, superior development as determined by cleavage,
blastocyst formation, and hatching ability was associated with
lower zona birefringence intensity parameters. When early
zygote-stage embryos were selected and assorted in groups
based on zona birefringence (high/medium/low), the group of
embryos derived from high-birefringence zygotes displayed a
significantly compromised developmental potential compared
with low-birefringence zygotes. These results clearly show
that developmentally competent bovine oocytes/zygotes
exhibit lower zona birefringence intensity parameters.
Therefore, birefringence imaging of zona pellucida is a
suitable technique to predict bovine preimplantation embryo
development.
Correspondence should be addressed to M Koester; Email: [email protected]
Reproduction (2011) 142 1–14
Sperm proteasome and fertilization
Peter Sutovsky
Division of Animal Sciences, and Department of Obstetrics, Gynecology and
Women’s Health, University of Missouri-Columbia, Columbia, Missouri 65211-5300,
USA
The omnipresent ubiquitin–proteasome system (UPS) is an
ATP-dependent enzymatic machinery that targets substrate
proteins for degradation by the 26S proteasome by tagging
them with an isopeptide chain composed of covalently linked
molecules of ubiquitin, a small chaperone protein. The
current knowledge of UPS involvement in the process of
sperm penetration through vitelline coat (VC) during human
and animal fertilization is reviewed in this study, with attention
also being given to sperm capacitation and acrosome
reaction/exocytosis. In ascidians, spermatozoa release
ubiquitin-activating and conjugating enzymes, proteasomes,
and unconjugated ubiquitin to first ubiquitinate and then
degrade the sperm receptor on the VC; in echinoderms and
mammals, the VC (zona pellucida/ZP in mammals) is
ubiquitinated during oogenesis and the sperm receptor
degraded during fertilization. Various proteasomal subunits
and associated enzymes have been detected in spermatozoa
and localized to sperm acrosome and other sperm structures.
By using specific fluorometric substrates, proteasomespecific proteolytic and deubiquitinating activities can be
measured in live, intact spermatozoa and in sperm protein
extracts. The requirement of proteasomal proteolysis during
fertilization has been documented by the application of
various proteasome-specific inhibitors and antibodies. A
similar effect was achieved by depletion of sperm-surface
ATP. Degradation of VC/ZP-associated sperm receptor
proteins by sperm-borne proteasomes has been
demonstrated in ascidians and sea urchins. On the applied
side, polyspermy has been ameliorated by modulating
sperm-associated deubiquitinating enzymes. Diagnostic and
therapeutic applications could emerge in human reproductive
medicine. Altogether, the studies on sperm proteasome
indicate that animal fertilization is controlled in part by a
unique, gamete associated, extracellular UPS.
Correspondence to P Sutovsky; Email: [email protected]
*****
*****
Julio 2011
12
Eventos Próximos
Julio 2011
13
Julio 2011
14
Sitios de Interés
Agrociencia
http://www.colpos.mx/agrocien/agrociencia.htm
Animal
http://www.animal-journal.eu/
Animal Reproduction
http://www.cbra.org.br/publicacoes/animalreproduction/issues.do
Animal Reproduction Science
http://www.sciencedirect.com/science/journal/03784320
Biology of Reproduction
http://www.biolreprod.org/
Ciencia
http://www.revistaciencia.amc.edu.mx/
Domestic Animal Endocrinology
Journal of Animal Science
http://jas.fass.org/
Journal of Dairy Science
http://jds.fass.org
Journal of Dairy Research
http://journals.cambridge.org/action/displayJournal?jid=DAR
Journal of Reproduction and Development
http://www.jstage.jst.go.jp/browse/jrd
Livestock Science
Manejo lechero
http://www.manejolechero.com/
Nature
http://www.nature.com/nature/index.html
Julio 2011
15
Physiological . Reviews
http://physrev.physiology.org/
Proceedings of the National Academy of Sciences of the United States of America
http://www.pnas.org/
Reproduction
http://www.reproduction-online.org/
Reproduction in Domestic Animals
http://www.wiley.com/bw/journal.asp?ref=0936-6768
Reproduction, Fertility and Development
http://www.publish.csiro.au/nid/44.htm
Revista Mexicana de Ciencias Pecuarias
http://www.tecnicapecuaria.org.mx/index2.php
Science
http://www.sciencemag.org/
The American Association of Bovine Practitioners
http://www.aabp.org/
The Dairy Cattle Reproduction Council (DCRC)
http://www.dcrcouncil.org/index.html
The Veterinary Record
http://veterinaryrecord.bvapublications.com/
Theriogenology
http://www.sciencedirect.com/science/journal/0093691X
Veterinary Clinics of North America: Food Animal Practice
http://www.vetfood.theclinics.com/
Veterinaria México
http://www.fmvz.unam.mx/fmvz/revvetmex/revvetmex.htm
Julio 2011
16
Julio 2011
17

Julio 2011 - FMVZ-UNAM

Transcription

Similar documents

SNU Rally at the Fallon Cantaloupe Festival September 2012

Livestock Opportunity - Indian Agricultural Program of Ontario

Headlocks Boost Reproductive Efficiency

Cow comfort and lameness on British Columbia dairy farms

7000 Head Herd Dispersal

Life in Palm Beach County - Digital Collection Center

uro-Star Indexes

Summer 2013 - Afon Veterinary Centre

November/December - Pharo Cattle Company

The life of: dairy cows - Compassion in World Farming